Process of making anthraquinones



" anhydrideand chlorobenzene,'etc.

v In thesynthesis of'anthraquinona-or its Patented Jan. 31, 1933 UNITED; S TES Dmmrs or BUFFALO, (NEW Yonx, jAssiGnoR T0 NA'r'IoNaIJ ANILILTE a cimmcai. COMPANY, INC, or NEW Yoax, NLY, A coaroaa'rron. or NEW YORK PROCESS or MAiIILiG Ame-ane one- No Drawing.

This invention relates to the manufacture andproduction of anthraquinoneg,or ts derivatives or analogues 1 It Well known that complex mtermedlate reaction products or compounds are iformedwhen phthalic anhydride, or ts derivatives such as, for example, chloro'phthal 'c anhydride, etc., are condensedwith benzene or derivatives. of benzene, or with other aromatic hydrocarbons or theirydemvatives such as, for example, tchlorobenzene, toluene, chlorotoluene, naphthalene, etc., by

means of the Friedel-Crafts reactionusing anhydrous aluminum chloride asthe combining or condensing agent. The condensation reaction is usually; carried-out in the resence of asolvent, such .as carbon disulode, petroleum ether, benzene, etc. These complex reaction, products "or compounds, which appear ,to contain allofthe alum num and a part of the chlorine of the aluminum chloride entering into the reaction, are easily decomposed by dilute acids to give the corresponding; free i aromatic acylbenzolc acid.

For example, in the condensation of phthalic,

an evolved and thereis formed an intermediate complex reaction product orcompound which upon subsequent-treatment with diluteiacid produces benzoyl-Q-benzoic acid-(o-benzoylbenzoic acid). Ina similar or analogous manner, p-toluyl-o-benzoicacid can-be obtained from the complex compound produced by condensing Vphthalic anhydrideflwith toluene, (chlor-4'-benzoyl)-2-benzoic acid from the product produced from phthalic derivatives or analogues, hereinafter referred to generallyas anthraquinonebodies, it has been heretofore the practice, so far asI am aware, to first decompose andconvert the complex intermediate reaction products or vcompounds above mentioned (hereinafter referred to generally as o-aroylbenzoic-aluminum chloride compounds) into the-corre- "b spondin'g free 'o-aroylbenzoicacid, and to V The presentinventionis based on the'disoff theexc'ess ofbenzene aroy lbenzoic-aluminum chloride Application filed November 21',"'1 923. Seria1 No, 676,5163.

subseduentlysubject the-free obtained. to the action of sulfuric acid, whereby an anthraquinone body is produced, For example, 'o-benzoyhbenzoic acid; p,-toluyl-'o benzoic acid, or: (chlor-4-benzoyl) -2-'benzoic acid when treated under suitableyconditions With sulfuric-acid of'suitable strength give V respectively; anthraquin'one, beta-methylam, v thraquinone, and beta-chloranth'raquinone.

covery that it is not necessary to prepare and isolate the free o-aroylbenzoicacids in the synthetic production of anthraquinone bodies but that anthraquinonebodies canjbe produced by treating the complex intermedi ate reaction-products. above mentioned, that is, o-a-roylbenzoic aluminum chloride coinp'ound's', directlyj-Withsulfuric acid of-suit able strength and under proper conditions.

For example, I have found that the complex reaction-product"obtained by condensing phthalic anhydrid'e with benzene in the presence of anhydrous aluminum chloride and excess of benzene, and-[subsequently distilling V ,prefer'ably' under dlmlnlshed pressure, gives, when treated With concentrated sulfuric acid under suitable conditions, an "excellent yield of; anthra qumone of good quality.

I havealso found hat beta-chloranthra quinone and 'beta methylanthraquinonea can be similarly produced by subjecting to the action of sulfuric'acid theirrespective complex reactlon-product, as obtained, for example, by: condensing phthalic anhydride with chlorobenzene or with toluene respectively in. the presence of aluminum chloride.

Other anthraquinonebodiesmay be similarly prepared from their corresponding 0- a g V compounds. The complex reaction-products employedv canbe obtained andisolated inanysuit able manner; For "example, they inay be obtained f bycondensing a p-hthalic anhydride body .95 withan excess of an au'onr aticv body b any suitable processand may be subsequent yiisolated any suitable manner, for example, by .distilllngofi the excess 'of the ,aromatic 'ody, preferably under reducedfpressure.

Thevmass i Preferably kept vvell stirred o procedure is to gradually addthe o-aroyl-T benzoic-aluminum chloride compound' in "a dry pulverized state, orin small; lumps or 5 particles, to sulfuric acid at a suitable tem-' agitated during the condensation and distillation. In the final reaction-productunde composed aluminum chloride also may a be benzoic-aluminurn chloride compound may also; be present;

' I" carrying out theinvention, a preferred perature and to subsequently recover the anthra'quin'one so formed inIany suitable and i 4 well knownmanner. V Infsome cases it" may'ibe advanta The following specific examples will lfu'rt er illustratetheinvention, but it is under to. The parts arebyweight. Example 1. 1 part of the aluminum chloride compound (obtainable condensing phthalic anhydride with ben I l tood that the invention isnot limited therebenzoylbenz oicszene in the presence of, anhydrous aluminum chloride and excess of ben zene, and subsequently distilling-off the excess benzene from the reaction-mass, preferably under diminished'pressure at least toward the end'of the i distillation) is slowly" added to about three partsoof well stirred 98-100 percent sulfuric 7 acid at a temperatureof about 130 135"C., j carebeingltaken that the reaction-massdoes not foam over, ,it -being controlledin-part I by therate'of mixing the-ingredients, After a 1 allof the benzoylbenzo'ic-a-luminum chloride Y aboutf'an hour;- or untilzthe reaction 'iscompleted; The well stirred reaction-mass 'ispthen allowedto cool to about 10094109 C about ,1. part of ice or cold water. is then added, and.

the mixture is then poured intoiabout -;30

parts of water; On cooling, thejanthraquin- 'onejs filtered' ofil, washed with water-and then with ,3 percent caustic alkali'solution,

and finally withhot water until substantially free from'alkali.- It may be further purified in any suitable manner,

In the above example, sulfuric acid of 'otheri'strengthaiand also other temperatures, 7 maybe employed, for-example,90 to 180C. As a rule, weaker acidsirequirehigher'temj dride at about 90?-100 maybe employed. j v

1 Within limits the weaker the acid the greater the number of parts of it which areemployedh trample 2.?The '7 initial materials, the. speci peratures and stronger acids lower tempera- .tures. Forexample, percent sulfuric acid at about 160-180 V C. or oleum containing about lO'to 15percent freeflsulfuric anhyfic conditions andthe procedure are the geous to useboricacid with the sul-.

I thraquinone body, for example, particularly part. of (chlorl' benzoyl) -2=benzoic-alumichloride and excess of chlor obenzene andsub- I sequently removing the excess chl'orobenzene 'bydistilling the reaction-mass under dimin? ished pressure) is substitutedin place; of the 1 part of benzoylbenzoic-aluminumchloride compound. r Y

1 Ifin Example 1,-the benzoylbenzoicalw 'num chloride'coni pound (obtainable by con- 'densing, phthalic anhydride with chlorobenzene in the presence of anhydrous aluminum minum'chloridejcom'pound is replaced by an equivalent, quantity of p-toluyLo-benzoic pounds mayalso be substituted for'the' benzoylbenZoic-aluminum' chloridecom ound.

"In-some cases the o-aroylbenz'oima uminum G; for the production (of the corresponding an-' in the naphthalene series: a

se chloride compound-may be treated vwith sul furl? i at 5 temperatures as '1ow1-as40 60 TheihydlOgel'i ghlorid i n jo r i g V the condensation by treating lolflroylben; zoic-alumi'num chloride compounds with 11;

furic acid, as welll as the aluminum sulfate 7 fOl'IIlGClflll the reactlon, maybe recovered in r any suitablemannenf It willthris"beseen' that anthraquinone bodies can bepr'epared by the direct action :of sulfuric acid on -the complex, intermediate reaction-products obtainableby the conden sation of phthalic anhy'dride bodies with are-, matic bodies such as benzene, toluene, chlorobenzene, etc; 3 by' means' of! the Fr'ie'del e g V Crafts reactionusinganhydrous aluminum compound has be'enadded, the mixture is'kept at a temperature of about I3O +I40 CQfor agent": v Y Y The process has the advantage of avoiding" the necessity of preparing and i's'olati'ng'1the freeio-aroylbenzoic acid, bodies in the ynthetic'production of anthraquinon'es'.

chloride 'as the condensing 0 =combining I D-In t'heclaimsyit; will be under tood fthat t the term strong sulfuric acid denotes" sul furicacid havingastrength of about '70to e 1 00"per cent and oleum (that 'i s,.'fuming sulf furic acid) which'contains not to-exceedr fi per centifree suliuric anh d id e; x 1 I'claimz y an 'o-aroylbenzoic-aluminum chloride com- 1. In the manufacture of an anthraquinone r body froma reaction mixture containing pound and a; solvent with 'anram ount of strong sulfuriciaci-d 'sufiicient to producean :anthraquinonebodyand 'recovering the an.

pound -to strong'sulfuricacid maintained "at 7' a'temperatur'enotlessthan'aboutQQ?CF11}4 aluminum chloride compound, there eanbe s I obtained -beta-methylanthraquinone. Other oaroylbenz'oic aluminum chloride com o aroylbenzoic-aluminum 3. The process of making an anthraquin- 7 5. The process of making an anthraquinone body which comprises heating an o-benzoylbenzoic-aluminum chloride compound with an amount of strongsulfuric acid sufiicient to produce an anthraquinone body and recovering the anthraquinone body from the resulting mixture.

6. The process of making an anthraquinone body which comprises heating an o-benzoylbenzoic-aluminum chloride compound with about percent sulfuric acid at a temperature of about 160 to 180 C. p

7 Theprocess of making an anthraquinone body which comprises heating an o-benzoylbenzoic-aluminum chloride compound with about 10 to 15 per cent oleum at a temperature of about to C.

8. The process of making an anthraquinone body which comprises graduall adding an o-aroylbenzoic-aluminum c loride compound to strong sulfuric acid, maintained at a temperature of about 90 to 180 C. whereby an anthraquinone body is produced.

9. The process of making'an anthraquinone body which comprises heating an chloride compound with strongsulfuric acid at a ringclosing temperature between 90 C. and 180 7 C. whereby an anthraquinone body is pro- 7 V duced.

10. The process of making an anthraquinone body which comprises heating an o-benzoylbenzoic-aluminum chloride compound with 98 to 100 percent sulfuric acid a at a temperature of about to C.

In testimony whereof I afiix my signature.

LLOYD C. DANIELS.

CERTIFICATE OF CORRECTION.

Patent No. 1,895,788. January 31, 1933 LLGYD G, DANILJL It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction. as follows: Page 2, line 121, claim 1, after "solvent" insert the words "the improvements which comprise distilling off the solvent under diminished pressure, and heating the residual mixture containing the o-aroylhenzeic-aluminum chloride compound"; and that the said Letters Patent should be read with this correction therein that the same may contorm to the record of the case in the Patent Office.

Signed and sealed this 9th day of May, A. D. 1933.

5, Moore (Seat) Acting Commissioner of Patents. 

